Effectiveness of three-dimensional printing artificial vertebral body and interbody fusion Cage in anterior cervical surgery

Abstract

To evaluate the effectiveness of three-dimensional (3D) printing artificial vertebral body and interbody fusion Cage in anterior cervical disectomy and fusion (ACCF) combined with anterior cervical corpectomy and fusion (ACDF). The clinical data of 29 patients with multilevel cervical spondylotic myelopathy who underwent ACCF combined with ACDF between May 2018 and December 2019 were retrospectively analyzed. Among them, 13 patients were treated with 3D printing artificial vertebral body and 3D printing Cage as 3D printing group and 16 patients with ordinary titanium mesh Cage (TMC) and Cage as TMC group. There was no significant difference in gender, age, surgical segment, Nurick grade, disease duration, and preoperative Japanese Orthopaedic Association (JOA) score, visual analogue scale (VAS) score, and Cobb angle of fusion segment between the two groups ( P>0.05). The operation time, intraoperative blood loss, hospitalization stay, complications, and implant fusion at last follow-up were recorded and compared between the two groups; JOA score was used to evaluate neurological function before operation, immediately after operation, at 6 months after operation, and at last follow-up; VAS score was used to evaluate upper limb and neck pain. Cobb angle of fusion segment was measured and the difference between the last follow-up and the immediate after operation was calculated. The height of the anterior border (HAB) and the height of the posterior border (HPB) were measured immediately after operation, at 6 months after operation, and at last follow-up, and the subsidence of implant was calculated. The operation time of 3D printing group was significantly less than that of TMC group ( t=3.336, P=0.002); there was no significant difference in hospitalization stay and intraoperative blood loss between the two groups ( P>0.05). All patients were followed up 12-19 months (mean, 16 months). There was no obvious complication in both groups. There were significant differences in JOA score, VAS score, and Cobb angle at each time point between the two groups ( P<0.05). There was an interaction between time and group in the JOA score ( F=3.705, P=0.025). With time, the increase in JOA score was different between the 3D printing group and the TMC group, and the increase in the 3D printing group was greater. There was no interaction between time and group in the VAS score ( F=3.038, P=0.065), and there was no significant difference in the score at each time point between the two groups ( F=0.173, P=0.681). The time of the Cobb angle interacted with the group ( F=15.581, P=0.000). With time, the Cobb angle of the 3D printing group and the TMC group changed differently. Among them, the 3D printing group increased more and the TMC group decreased more. At last follow-up, there was no significant difference in the improvement rate of JOA score between the two groups ( t=0.681, P=0.502), but the Cobb angle difference of the 3D printing group was significantly smaller than that of the TMC group ( t=5.754, P=0.000). At last follow-up, the implant fusion rate of the 3D printing group and TMC group were 92.3% (12/13) and 87.5% (14/16), respectively, and the difference was not significant ( P=1.000). The incidence of implant settlement in the 3D printing group and TMC group at 6 months after operation was 15.4% (2/13) and 18.8% (3/16), respectively, and at last follow-up were 30.8% (4/13) and 56.3% (9/16), respectively, the differences were not significant ( P=1.000; P=0.264). The difference of HAB and the difference of HPB in the 3D printing group at 6 months after operation and last follow-up were significantly lower than those in the TMC group ( P<0.05). For patients with multilevel cervical spondylotic myelopathy undergoing ACCF combined with ACDF, compared with TMC and Cage, 3D printing artificial vertebrae body and 3D printing Cage have the advantages of shorter operation time, better reduction of height loss of fusion vertebral body, and maintenance of cervical physiological curvature, the early effectiveness is better.